Schrotz



NE 2 Sheets-Sheet 1 K TZ CHANISM FOR TOP ROLLS CARRYING A DRAFTINGASSEMBLY OF A SPINNING MA Filed April 13. 1959 SCHRO Nov. 1, 1960 LOCKME INVENrOP Nov. 1, 1960 LOCK MECHANI A DRAFTING Filed April 15. 1959 SMF ASSE

TOP ROLLS LY OF A SP SCHROTZ INN CARR NG ARM 0F MACHINE 2 Sheets-Sheet 2mmswrox Kw 5M5,

United States Patent LOCK MECHANISM FOR TGP ROLLS CARRYING ARM OF ADRAFTING ASSEMBLY OF A SPIN- NING MACHINE Kiirt Schrotz, Michelberg,Germany, assignor to SKF Kugellagert'abriken G.m.b.H., Schweiufnrt,Germany Filed Apr. 13, 1959, Ser. No. 805,810

Claims priority, application Germany June 12, 1958 9 Claims. (Cl.19-135) The present invention relates to drafting assemblies of spinningmachines.

Such drafting assemblies include top rolls carrying arms which areconventionally movable between lower operating and upper inoperativepositions.

More particularly, the present invention relates to a lock structurewhich will lock such a top rolls carrying arm both in its loweroperating position as well as in its upper inoperative position.

'Oneof the objects of the present invention is to provide a lockstructure of the above type which renders it unnecessary to depress thetop rolls carrying arm when it is desired to release the latter formovement to its upper inoperative position. Although locks are knownwhich can be released upon depression of the top rolls carrying armslightly so that the operator while depressing the arm with one hand canrelease the lock with the other hand, these types of lock mechanisms arenot suitable in constructions where a relatively large load is appliedto the top rolls carrying arm since with such a large load it is notpossible for the operator to depress the arm further in order to releasea conventional lock of this type.

Another object of the present invention is to provide a lock structurewhich is made up of a relatively small number of parts which occupy arelatively small space so that the space required for a series ofdrafting assemblies according to the invention is not undesirablyincreased in order to accommodate the lock structure.

A further object of the present invention is to provide a lock structureof the above type which does not extend below the top rolls carrying armso that when the latter is in its upper inoperative position free accessmay be had to all of the parts of the drafting structure in order toservice these parts.

An additional object of the present invention is to provide a lockstructure of the above type which will not only hold the top rollscarrying arm in its lower operative and its upper inoperative positions,but which will also determine the upper inoperative position of the toprolls carrying arm.

It is also an object of the present invention to provide a lockstructure of the above type made up of simple rugged elements whichcooperate with each other in such a way that the forces are evenlydistributed through the parts of the mechanism so that there will be nolocalized wearing away of any one part of the mechanism during use ofthe structure of the invention.

With the above objects in view the present invention includes in adrafting assembly of a spinning machine a support and a top rollscarrying arm turnably connected to the support for movement between alower operating and an upper inoperative position. In accordance withthe present invention a toggle linkage means is connected to the supportand to the arm and moves between one end position slightly beyond a deadcenter position of the toggle linkage means through the dead centerposition to an opposite end position where the parts of the togglelinkage means are substantially at the end of their possi- "ice blemovement with respect to each other, this toggle linkage means lockingthe top rolls carrying arm in its lower operating position when thetoggle linkage means is in the said one end position thereof and lockingthe top rolls carrying arm in its upper inoperative position when thetoggle linkage means is in the said opposite end position thereof.

The novel features which are considered as characteristic for theinvention are set forth in particular in the appended claims. Theinvention itself, however, both as to its construction and its method ofoperation, together with additional objects and advantages thereof, willbe best understood from the following description of specificembodiments when read in connection with the accompanying drawings, inwhich:

Fig. 1 is a diagrammatic side elevational view of a drafting assemblywhich includes the structure of the invention;

Fig. 2 is a sectional elevational view on an enlarged scale, as comparedto Fig. 1, of that portion of the drafting assembly of Fig. 1 to whichthe lock structure of the invention is connected;

Fig. 3 is an end view of the structure of Fig. 2 as seen in thedirection of the arrows III of Fig. 2, part of the structure beingbroken away in Fig. 3 so as to clearly illustrate the elements of thelock structure of the invention;

Fig. 4 shows the position which the parts of Fig. 2 take when the toprolls carrying arm is in an upper inoperative position, this arm beingshown in its lower operating position in Fig. 2; and

Fig. 5 illustrates the position of the parts of Figs. 2 and 4 at a pointintermediate the positions thereof illustrated in Figs. 2 and 4.

Referring now to the drawings, it will be seen that the structureillustrated therein includes a top rolls carrying arm 1 which is ofU-shaped cross section and which has a top wall formed with alongitudinally extending slot 1' which terminates short of the ends ofthe arm 1. This slot 1 enables in a known way a plurality of supportunits for the saddle arms 2 to be located between the side walls of thearm 1 for adjustable longitudinal movement therealong so that thepositions of the saddle arms 2 along the arm 1 can be adjusted in aknown way. These saddle arms 2, which are conventional, carry in a knownway the saddles 3, respectively, which in turn are connected in a knownWay with the shafts of the several pairs of top rolls 4 whicch cooperatewith the bottom rolls 5 shown in Fig. 1 also in a conventional manner.An unillustrated loading means cooperates in a known way with the toprolls 4 to urge the latter downwardly toward the bottom rolls 5. The toprolls carrying arm 1 is turnable upwardly from the lower operatingposition thereof illustrated in Fig. 1 to an upper inoperative position.Thus, a stationary support in the form of bracket 6 carries a forwardpivot pin 7 on which the top rolls carrying arm 1 is turnable. Thesupport 6 includes a pair of parallel plates interconnected by aplurality of spacer pins one of which simultaneously forms the pivot pin7, and these parallel plates 6 are of a springy material and are formedwith aligned openings through which the stationary support bar 9extends, each of the plates 6 being formed with a slit extending fromthe opening which receives the bar 9 to the outer edge of the plate 6.These plates 6 are also formed with aligned openings which receive a nutto which a bolt 8 is threaded, the head of the bolt engaging a bottomedge of each plate 6 at the rear of the latter so that when the bolt 8is tightened the slit of each plate 6 will tend to close and thus theplate 6 will tightly grip the stationary bar 9. A cover 6 made of sheetmetal or plastic, for example, encloses the support 6, this cover 6'being formed with openings through which the support bar 9 passes andthe cover 6' covering the opposite sides 3 as well as the rear of thesupport 6. It will be noted that the cover 6' is open at its bottom soas to render the bolt 8 accessible for tightening or loosening.

At its rear end which is adjacent to the support 6, the arm 1 carries apivot pin 10 which also has a portion acting as a stop, as will beapparent from the description below. This pivot pin 10 pivotally carriesa lever 11 which forms part of a toggle linkage means. The lever 11 ismade up of a pair of identical lever portions located in side by siderelation and spaced slightly from each other, these portions of thelever 11 being turnable on the pin 10 or being fixed to the latter andthe pin 10 in this case is turnably carried by the arm 1 in the sidewalls thereof, as is particularly apparent from Fig. 3. A second lever12 of the toggle linkage means extends into the space between the pairof lever portions which form the lever 11, and this lever 12 ispivotally carried by a pivot pin 13 which is directly carried by thesupport 6. Thus, the levers 11 and 12 have overlapping portions, andthese overlapping portions of these levers are formed with cutouts whichalso overlap each other. Thus, the pair of lever portions which form thelever 11 are formed with substantially triangular cutouts 11 which arealigned with each other, while the lever 12 is formed with an elongatedcutout 12 extending along an arc of a circle whose center is in the axisof the pivot pin 13. An operating pin 14 which is parallel to the pins10 and 13 extends through the cutouts 11' and 12' and is carried at itsends by the side walls of an operating lever 15 which is pivotallycarried by end portions of the pin 13 which project through and beyondthe plates 6 as well as the side walls of the cover 6. As is apparentfrom Fig. 1 the operating lever 15 extends over and longitudinally alongthe arm 1 in the position of the part shown in Fig. 1, and as a resultof its length the lever 15 can be easily operated to place the arm 1 inits lower operating or upper inoperative position even when the loadingpressures for the top rolls are relatively high.

Referring now to Fig. 2, when the center of the operating pin 14 islocated in the straight line which connects the centers of the pins 10and 13, the toggle linkage means is in its dead center position. In theposition of the parts shown in Fig. 2, the center of the pin 14 isslightly to the left of the straight line connecting the centers of thepins 10 and 13, so that in this position of the parts, which is thelower operating position of the arm 1, the operating pin 14 is slightlybeyond the dead center position of the toggle linkage means. In theposition of the parts shown in Fig. 2, if the arm 1 is raised so as toturn in a clockwise direction around the pivot pin 7, the lever 11 willtend to push the pin 14 downwardly against the lever 12, so that thetoggle linkage means blocks such movement of the arm 1, and furthermore,any tendency of the operating pin 14 to turn in a counterclockwisedirection around the pin 13 during an attempt to raise the arm 1 in theposition of the parts shown in Fig. 2 will only tend to press theoperating lever 15 against the arm 1 in a downward direction so that thearm 1 is effectively locked in the position of the parts shown in Figs.1 and 2. It will be noted that in the position of the parts shown inFig. 2 the operating pin 14 is at the upper apex of the substantiallytriangular cutouts 11' of the portions of the lever 11.

As may be seen from Figs. 2 and 3, the lever 12 has a hook portion 12"integrally formed therewith and extending therefrom in the manner shownmost clearly in Fig. 2, and a Wire spring 16 has a substantiallyU-shaped portion embracing the lower portion of the lever 12 as viewedin Fig. 2 the legs of this U-shaped portion of the wire spring 16 beingcoiled about the pin 13 on the opposite sides of the plate or lever 12and extending to the rear edges of the pair of plates of the support 6where the outer extremities of the spring 16 are bent so as to overlapand engage these rear edges, so that the spring 16 continuously urgesthe lever 12 in a clockwise direction,

as shown in Fig. 2, so as to maintain the left end of the cutout 12', asviewed in Fig. 2, in engagement with the operating pin 14. The thicknessof the pair of portions of the lever 11 is chosen, in accordance withthe particular requirements of the structure of the invention, and inrelation to the thickness of the walls of the lever 15, in such a waythat the bearing surface provided by the portions of the lever 11 forthe operating pin 14 is as great as the area of contact between the pin14 and the lever 15, so that in this way the forces which the pin 14 isrequired to withstand are distributed over a sufficient area of the pin14 and furthermore localized wear of the pin 14 is avoided.

In order to unlock the arm 1 in order to raise the latter to its upperinoperative position illustrated in Fig. 4, the operator turns theoperating lever 15 in the direction indicated by the arrow A in Fig. 1.During this turning of the lever 15, the operating pin turns with thelever 15 around the pin 13 in a clockwise direction, as viewed in Fig.2, and the pin 14 simply rides along the right edge of the cutouts 11',as viewed in Fig. 2, turning the lever 11 until the pin 14 engages thebase of the triangular cutouts of the portions of the lever 11. In thisposition the arm 1 simply rests as a result of its own Weight in itsoperating position with the top rolls 4 engaging the bottom rolls 5, sothat if desired the arm 1 can again be locked at this time. However, ifit is desired to turn the arm 1 upwardly to its inoperative position andto lock it in this latter position, the operator continues to turn thelever 15 in a direction of the arrow A of Fig. 1, so that the operatingpin 14 which now engages the base of the triangular cutout of eachportion of the lever 11 pulls to the right, as viewed in Figs. 2 and 5,on the lever 11 so as to act through the pin 10 on the arm 1 to turn thelatter around the pin 7 in a clockwise direction, as viewed in Fig. 2.Of course, during the turning of the operating pin 14 with the lever 15the spring 16 turns the lever 12 so as to maintain the left end of theslot 12', as viewed in Fig. 2, in engagement with the pin 14. Thus, thehook portion 12" turns upwardly at this time. As soon as the operatingpin 14 acts through the lever 11 on the pin 10 to pull the arm 1 in aclockwise direction around the pin 7, the pin 10 starts to turndownwardly around the pin 7 and thus the pin 10 and the hook portion 12"approach each other and then engage each other, the intermediate portionof the pin 10 which is located between the pair of plates which form thelever 11 forming a stop portion which cooperates with the hook portion12 of the lever 12. During the continued turning of the operating lever15, the downwardly turning pin 10 with its intermediate stop portionengaging the hook portion 12" acts on the lever 12 through the hookportion 12" to prevent the spring 16 from causing the lever 12 to followthe pin 14, and at this time parts will have the position indicated inFig. 5, the pin 10 continuing to ride downwardly along the tip of thehook portion 12" until this hook portion can snap over the stop portionof the pin 10. As soon as the central stop portion of the pin 10 ridesover the tip of the hook portion 12", the spring 16 snaps the lever 12around to the position shown in Fig. 4 so that the hook portion 12" isnow located over the pin 10. The arm 1 is shown in its upper inoperativeposition in Fig. 4, and it will be noted that because the hook portion12" is over the pin 10, any tendency of the arm 1 to turn downwardlyfrom the position of Fig. 4 will be resisted by the hook portion 12", sothat the arm 1 is reliably locked in its upper inopertive position Withthe structure of the invention, when this structure has the positionshown in Fig. 4. It will be noted that in the position of the togglelinkage means illustrated in Fig. 4, the components of the togglelinkage means have moved with respect to each other substantially to theend of their possible movement with respect to each other on the rightside of the line of centers connecting the centers of the pins 10 and13.

As is apparent from Fig. 4, when the operator desires to turn the arm 1to its operating position indicated in Fig. 1, it is only necessary toturn the operating lever 15 in a direction opposite to the directionindicated by the arrow A of Fig. 1. This turning of the lever 15 willcause the pin 14 to turn the lever 12 in a counterclockwise direction,as viewed in Fig. 4, in opposition to the spring 16, so as to move thehook portion 12" away from the pin and thus the arm 1 can now movedownwardly toward its operating position where the top rolls 4 engagethe bottom rolls 5. As was mentioned above, the arm 1 always tends toreturn to its operating position due to its own weight and the weight ofthe parts connected thereto. Thus, as the hook portion 12" turns in acounterclockwise direction from the position shown in Fig. 4 the arm 1due to its own weight will tend to turn around the pin 7 in acounterclockwise direction and thus as soon as the hook portion 12" hasturned downwardly through a sufiicient distance the pin 10 will againride along the tip of the hook portion 12". Of course, thecounterclockwise turning of the lever will cause the operating pin 14 tomove upwardly in the triangular cutouts 11' and the pin 14 will moveupwardly from the position of Fig. 4 to that of Fig. 5. The downwardlyturning arm 1 will act through the stop portion formed by theintermediate part of the ipn 10 on the tip of the hook portion 12" toturn the lever 12 to the position shown in Fig. 5 while the lever 11pulls to the left, as viewed in Fig. 5, on the pin 14 so as to urgethelever 15 toward the position thereof shown in Fig. l, and in this waythe weight of the arm 1 and the parts connected thereto willautomatically continue the movement of the parts beyond the positionshown in Fig. 5 back toward the position indicated in Fig. 2. In thisway the entire lever 11 will move to the left beyond the position shownin Fig. 5 while the pin 10 turns upwardly from the position of Fig. 5 tothat of Fig. 2, and when the pin 10 moves upwardly away from the tip 12"the spring 16 will turn the lever 12 in a clockwise direction so thatthe left end of the slot 12 will engage the pin 14, as indicated in Fig.2. When the arm 1 has reached its operating position the pin 14 will belocated slightly to the right of the dead center of the toggle joint, asviewed in Fig 2 and the arm 15 will still be slightly above the positionthereof shown in Fig. 1. The operator will then move the arm 15 down tothe position shown in Fig. l and this will result in turning of the pin14 through and beyond the dead center of the toggle joint to theposition indicated in Fig. 2, thus locking the parts in the operatingposition as pointed out above. Upon return of the lever 15 to theposition of Fig. 1 the pin 14 will have moved slightly beyond the deadcenter position of the toggle linkage means, as described above, sothatthe arm 1 is again locked in its operating position.

Of course, only one embodiment of the invention has been describedabove. Variations are possible in the details of the structure. Forexample, the form of the individual levers of the toggle linkage meansand in their connection with the top rolls carrying arm 1 and thesupport 6 may vary. Also, there may be variations with respect to thehook portion 12" Without detracting from the advantages of theinvention. Furthermore, it is possible to adjust the position of theoperating pin 14 with respect to the lever 15 so as to be able tocontrol the extent through which the arm 1 turns from its loweroperatingposition to its upper inoperative position. In the same way,the path of turning of the arm 1 can be adjusted by choosing a propersize for the cutouts 11 of the portions of the lever 11, and the size ofthese cutouts may be rendered adjustable by providing elements which areslidably connected to the portions of the lever 11 to be fixed to thelatter in an adjusted position over lapping the cutouts 11' so as toregulate the effective size thereof. Furthermore, instead of a pair ofindependent plate portions forming the lever 11, this lever 11 may havethe form of a single plate portion which is bifurcated at its lower end,and of course in this case the end of such a 6 lever would be displacedfrom the plane of the hook portion 12" so that the latter couldcooperate properly with the central stop portion of the pin 10.

It will be noted that the lock structure of the invention is composed ofrelatively small simple elements which occupy only a small amount ofspace which is part of the space occupied in any event by the arm 1 andsupport 6, so that the amount of space required for a series of draftingassemblies is not increased by the lock structure of the invention.Furthermore, it will be seen that when the arm 1 is in its upperinoperative position indicated in Fig. 4, none of the lock structure ofthe invention extends to the left, as viewed in Fig. 4, beyond the arm1, so that all of this space is freely accessible for convenientservicing of the structure. Also, none of the structure of the inventionis so positioned that fibers will collect thereon, so that the structureof the invention also remains perfectly clean.

It will be understood that each of the elements described above, or twoor more together, may also find a useful application in other types ofdrafting assemblies differing from the types described above.

While the invention has been illustrated and described as embodied inlock structures for drafting assemblies, it is not intended to belimited to the details shown, since various modifications and structuralchanges may be made without departing in any way from the spirit of thepresent invention.

Without further analysis, the foregoing Will so fully reveal the gist ofthe present invention that others can by applying current knowledgereadily adapt it for various applications Without omitting featuresthat, from the standpoint of prior art, fairly constitute essentialcharacteristics of the generic or specific aspects of this inventionand, therefore, such adaptations should and are intended to becomprehended within the meaning and range of equivalence of thefollowing claims.

What is claimed as new and desired to be secured by Letters Patent is:

1. In a drafting assembly of a spinning machine, in combination, astationary support; an elongated top rolls carrying arm pivotallycarried by said support for turning movement between a lower operativeand upper inoperative position; and toggle linkage means connected tosaid support and arm and movable between one end position slightlybeyond a dead center position of said toggle linkage means through saiddead center position to an opposite end position where the elements ofsaid toggle linkage means are substantially at the end of their possiblemovement with respect to each other, said toggle linkage means lockingsaid arm in said lower operative position thereof when said togglelinkage means is in said one end position thereof and said togglelinkage means locking said arm in said upper inoperative positionthereof when said toggle linkage means is in said opposite end positionthereof, said toggle linkage means including a first lever pivotallycarried by said arm, a second lever pivotally carried by said support,said first and second levers overlapping each other and beingrespectively formed with overlapping cutouts at their overlappingportions, and an operating pin extending through said overlappingcutouts; and an operating lever turnably carried by said support andcarrying said operating pin so that the latter moves during turning ofsaid operating lever.

2. In a drafting assembly of a spinning machine, in combination, astationary support; an elongated top rolls carrying arm pivotallycarried by said support for turning movement between a lower operativeand upper inoperative position; toggle linkage means connected to saidsupport and arm and movable between one end position slightly beyond adead center position of said toggle linkage means through said deadcenter position to an opposite end position where the elements of saidtoggle linkage means are substantially at the end of their possiblemovement with respect to each other, said toggle linkage means -lockingsaid arm in said lower operative position thereof when said togglelinkage means is in said one end position thereof and said togglelinkage means locking said arm in said upper inoperative positionthereof when said toggle linkage means is in said opposite end positionthereof, said toggle linkage means including a first lever pivotallycarried by said arm and a second lever pivotally carried by said supportand overlapping said first lever, one of said levers having a hookportion; and a stop portion with which said hook portion cooperates whensaid toggle linkage means is in said opposite end position thereof, saidstop portion and hook portion being respectively turnable along arcs ofcircles whose centers are displaced from each other.

3. In a drafting assembly of a spinning machine, in combination, astationary support; an elongated top rolls carrying arm pivotallycarried by said support for turning movement between a lower operativeand upper inoperative position; toggle linkage means connected to saidsupport and arm and movable between one end position slightly beyond adead center position of said toggle linkage means through said deadcenter position to an opposite end position where the elements of saidtoggle linkage means are substantially at the end of their possiblemovement with respect to each other, said toggle linkage means lockingsaid arm in said lower operative position thereof when said togglelinkage means is in said one end position thereof and said togglelinkage means locking said arm in said upper inoperative positionthereof when said toggle linkage means is in said opposite end positionthereof, said toggle linkage means including a first lever pivotallycarried by said arm and a second lever pivotally carried by said supportand overlapping said first lever, one of said levers having a hookportion; and a stop portion with which said hook portion cooperates whensaid toggle linkage means is in said opposite end position thereof, saidstop portion and hook portion being respectively turnable along arcs ofcircles whose centers are displaced from each other and said circlesintersecting each other when said stop portion and hook portion are inthe positions they take when said toggle linkage means is in saidopposite end position thereof.

4. In a drafting assembly of a spinning machine, in combination, astationary support; an elongated top rolls carrying arm pivotallycarried by said support for turning movement between a lower operativeand upper inoperative position; toggle linkage means connected to saidsupport and arm and movable between one end position slightly beyond adead center position of said toggle linkage means through said deadcenter position to an opposite end position where the elements of saidtoggle linkage means are substantially at the end of their possiblemovement with respect to each other, said toggle linkage means lockingsaid arm in said lower operative position thereof when said togglelinkage means is in said one end position thereof and said togglelinkage means locking said arm in said upper inoperative positionthereof when said toggle linkage means is in said opposite end positionthereof, said toggle linkage means including a first lever pivotallycarried by said arm and a second lever pivotally carried by said supportand overlapping said first lever, one of said levers having a hookportion; a stop portion with which said hook portion cooperates whensaid toggle linkage means is in said opposite end position thereof, saidstop portion and hook portion being respectively turnable along arcs ofcircles whose centers are displaced from each other and said circlesintersecting each other when said stop portion and hook portion are inthe positions they take when said toggle linkage means is in saidopposite end position thereof; and an operating lever operativelyconnected to said toggle linkage means for operating the same, saidlever moving said hook portion away from said stop portion when saidoperating lever is actuated to release said arm for movement from itsupper inoperative position back to its lower operative position.

5. In a drafting assembly of a spinning machine, in combination, astationary support; an elongated top rolls carrying arm pivotallycarried by said support for turning movement between a lower operativeand upper inoperative position; toggle linkage means connected to saidsupport and arm and movable between one end position slightly beyond adead center position of said toggle linkage means through said deadcenter position to an opposite end position where the elements of saidtoggle linkage means are substantially at the end of their possiblemovement with respect to each other, said toggle linkage means lockingsaid arm in said lower 0perative position thereof when said togglelinkage means is in said one end position thereof and said togglelinkage means locking said arm in said upper inoperative positionthereof when said toggle linkage means is in said opposite end positionthereof; said toggle linkage means including a first lever pivotallycarried by said arm and a second lever pivotally carried by said supportand overlapping said first lever, said second lever having a hookportion; and a stop portion carried by said arm, said hook portioncooperating with said stop portion carried by said arm for maintainingthe latter in its upper inoperative position when said toggle linkagemeans is in its opposite end position.

6. In a drafting assembly of a spinning machine, in combination, astationary support; an elongated top rolls carrying arm pivotallycarried by said support for turning movement between a lower operativeand upper inoperative position; and toggle linkage means connected tosaid support and arm and movable between one end position slightlybeyond a dead center position of said toggle linkage means through saiddead center position to an opposite end position where the elements ofsaid toggle linkage means are substantially at the end of their possiblemovement with respect to each other, said toggle linkage means lockingsaid arm in said lower operative position thereof when said togglelinkage means is in said one end position thereof and said togglelinkage means locking said arm in said upper inoperative positionthereof when said toggle linkage means is in said opposite end positionthereof, said toggle linkage means including a first lever, a pivot pinpivotally connecting said first lever to said arm and a second leverpivotally carried by said support and overlapping said first lever, saidsecond lever having a hook portion; and a stop portion carried by saidarm, said hook portion cooperating with said stop portion carried bysaid arm for maintaining the latter in its upper inoperative positionwhen said toggle linkage means is in its opposite end position, saidstop portion being formed by part of said pivot pin which pivotallyconnects said first lever to said arm.

7. In a drafting assembly of a spinning machine, in combination, astationary support; an elongated top rolls carrying arm pivotallycarried by said support for turning movement between a lower operativeand upper inoperative position; and toggle linkage means connected tosaid support and arm and movable between one end position slightlybeyond a dead center position of said toggle linkage means through saiddead center position to an opposite end position where the elements ofsaid toggle linkage means are substantially at the end of their possiblemovement with respect to each other, said toggle linkage means lockingsaid arm in said lower operative position thereof when said togglelinkage means is in said one end position thereof and said togglelinkage means locking said arm in said upper inoperative positionthereof when said toggle linkage means is in said opposite end positionthereof, said toggle linkage means including a first lever pivotallycarried by said arm, a second lever pivotally carried by said supportand overlapping said first lever, said first and second levers beingformed With cutouts at their overlapping portions and said cutouts alsooverlapping each other and said toggle linkage means including anoperating pin extending through said cutouts of said first and secondlevers; an operating lever carried by said support and carrying saidoperating pin for moving the latter so as to move said toggle linkagemeans between said end positions thereof, the size of the cutout of saidfirst lever determining the upper inoperative position of said arm.

8. In a drafting assembly of a spinning machine, in combination, astationary support; a forward pivot pin carried by said support; arearward pivot pin carried by said support rearwardly of said forwardpivot pin; a top rolls carrying arm connected by said forward pivot pinto said support for turning movement with respect to the latter; a thirdpivot pin carried by said arm for movement therewith around said forwardpivot pin; a first lever connected to said rearward pivot pin for tumingmovement with respect to said support around the axis of said rearwardpivot pin; a second lever connected to said third pivot pin for turningmovement with respect to said arm, said first and second leversoverlapping each other and being formed with cutouts at theiroverlapping portions and said cutouts also overlapping each other, thecutout of said first lever extending substantially along an arc of acircle whose center is in the axis of said rearward pivot pin; anoperating pin parallel to the other pins and extending through saidcutouts of said first and second levers; an operating lever pivotallycarried by said rearward pivot pin and fixedly carrying said operatingpin; and spring means cooperating with said first lever for urging thelatter to turn with respect to the axis of said rearward pivot pin in adirection which maintains one end of the cutout of said first lever inengagement with said operating pin.

9. In a drafting assembly of a spinning machine, in combination, astationary support; a forward pivot pin carried by said support; arearward pivot pin carried by said support rearwardly of said forwardpivot pin; a top rolls carrying arm connected by said forward pivot pinto said support for turning movement with respect to the latter; a thirdpivot pin carried by said arm for movement therewith around said forwardpivot pin; a first lever connected to said rearward pivot pin for tumingmovement with respect to said support around the axis of said rearwardpivot pin; a second lever connected to said third pivot pin for turningmovement with respect to said arm, said first and second leversoverlapping each other and being formed with cutouts at theiroverlapping portions and said cutouts also overlapping each other, thecutout of said first lever extending substantially along an arc of acircle whose center is in the axis of said rearward pivot pin; anoperating pin parallel to the other pins and extending through saidcutouts of said first and second levers; an operating lever pivotallycarried by said rearward pivot pin and fixedly carrying said operatingpin; spring means cooperating with said first lever for urging thelatter to turn with respect to the axis of said rearward pivot pin in adirection which maintains one end of the cutout of said first lever inengagement with said operating pin; and a hook portion fixed to saidfirst lever for turning move ment therewith and extending around saidthird pivot pin when said arm is in an upper inoperative position, saidoperating lever being manually turnable to move said first lever throughpressure of said operating pin thereon against the force of said springmeans in a direction which turns said hook portion away from said thirdpivot pin to release said arm for movement back to its operatingposition.

References Cited in the file of this patent UNITED STATES PATENTS

